Annual Review of Neuroscience,
Journal Year:
2024,
Volume and Issue:
47(1), P. 103 - 121
Published: April 10, 2024
The
cochlear
implant
(CI)
is
considered
the
most
successful
neuroprosthesis
as
it
enables
speech
comprehension
in
majority
of
million
otherwise
deaf
patients.
In
hearing
by
electrical
stimulation
auditory
nerve,
broad
spread
current
from
each
electrode
acts
a
bottleneck
that
limits
transfer
sound
frequency
information.
Hence,
there
remains
major
unmet
medical
need
for
improving
quality
with
CIs.
Recently,
optogenetic
cochlea
has
been
suggested
an
alternative
approach
restoration.
Cochlear
optogenetics
promises
to
more
information,
hence
hearing,
light
can
conveniently
be
confined
space
activate
nerve
within
smaller
tonotopic
ranges.
this
review,
we
discuss
latest
experimental
and
technological
developments
restoration
outline
remaining
challenges
en
route
clinical
translation.
Molecular Therapy — Methods & Clinical Development,
Journal Year:
2023,
Volume and Issue:
29, P. 202 - 212
Published: March 21, 2023
Sensory
restoration
by
optogenetic
neurostimulation
provides
a
promising
future
alternative
to
current
electrical
stimulation
approaches.
So
far,
channelrhodopsins
(ChRs)
typically
contain
C-terminal
fluorescent
protein
(FP)
tag
for
visualization
that
potentially
poses
an
additional
risk
clinical
translation.
Previous
work
indicated
reduction
of
efficacy
upon
FP
removal.
Here,
we
further
optimized
the
fast-gating,
red-light-activated
ChR
f-Chrimson
achieve
efficient
in
absence
FP.
Upon
removal,
observed
massive
amplitude
photocurrents
transfected
cells
vitro
and
optogenetically
evoked
activity
adeno-associated
virus
(AAV)
vector-transduced
auditory
nerve
mice
vivo.
Increasing
AAV
vector
dose
restored
but
was
confounded
neural
loss.
Of
various
modifications,
found
replacement
Kir2.1
trafficking
sequence
(TSKir2.1)
best
restore
both
with
only
mild
loss
few
months
after
dosing.
In
conclusion,
consider
f-Chrimson-TSKir2.1
be
candidate
translation
such
as
optical
cochlear
implants.
Frontiers in Neuroscience,
Journal Year:
2023,
Volume and Issue:
17
Published: Jan. 23, 2023
The
electrical
cochlear
implant
(eCI)
partially
restores
hearing
in
individuals
affected
by
profound
impairment
(HI)
or
deafness.
However,
the
limited
resolution
of
sound
frequency
coding
with
eCIs
limits
daily
situations
such
as
group
conversations.
Current
research
promises
future
improvements
restoration
which
may
involve
gene
therapy
and
optical
stimulation
auditory
nerve,
using
optogenetics.
Prior
to
potential
clinical
translation
these
technologies,
it
is
critical
that
patients
are
engaged
order
align
agendas
technological
advancements
their
needs.Here,
we
performed
a
survey
study
impaired,
an
eCI
means
rehabilitation.
We
distributed
questionnaire
180
adult
from
University
Medical
Center
Göttingen's
Department
Otolaryngology
who
were
actively
for
6
months
more
during
time
period.
Questions
revolved
around
needs,
willingness
accept
hypothetical
risks
drawbacks
associated
CI
(oCI).Eighty-one
participants
responded
questionnaire;
68%
greater
than
60
years
age
26%
had
bilateral
eCIs.
Participants
expressed
need
improving
performance
beyond
experienced
current
eCI.
Primarily,
they
desired
improved
speech
comprehension
background
noise,
ability
appreciate
music,
natural
impression.
They
engaging
new
technologies
restoration.
Notably,
least
concerned
about
hypothetically
receiving
necessary
oCI
implant;
but
reluctance
yet
be
evaluated
human
trial.This
work
provides
preliminary
step
development
technology
has
address
limitations
Hearing Research,
Journal Year:
2023,
Volume and Issue:
440, P. 108911 - 108911
Published: Nov. 4, 2023
For
individuals
with
severe
to
profound
hearing
loss
resulting
from
irreversibly
damaged
hair
cells,
cochlear
implants
can
be
used
restore
by
delivering
electrical
stimulation
directly
the
spiral
ganglion
neurons.
However,
current
spread
lowers
spatial
resolution
of
neural
activation.
Since
light
easily
confined,
optogenetics
is
a
technique
that
has
potential
improve
precision
activation,
whereby
visible
stimulate
neurons
are
modified
light-sensitive
opsins.
This
study
compares
activity
across
inferior
colliculus
auditory
midbrain
during
and
optical
in
cochlea
acutely
deafened
mice
opsin-modified
(H134R
variant
channelrhodopsin-2).
Monopolar
was
delivered
via
each
four
0.2
mm
wide
platinum
electrode
rings
at
0.6
centre-to-centre
spacing,
whereas
453
nm
wavelength
five
0.22
×
0.27
micro-light
emitting
diodes
(LEDs)
0.52
spacing.
Channel
interactions
were
also
quantified
threshold
changes
simultaneous
pairs
electrodes
or
micro-LEDs
different
distances
between
(0.6,
1.2
1.8
mm)
(0.52,
1.04,
1.56
2.08
mm).
The
activation
single
channel
approximately
half
monopolar
as
measured
two
levels
discrimination
above
(p<0.001),
there
no
significant
difference
pure
tone
acoustic
normal-hearing
mice.
During
micro-LED
stimulation,
minimal
for
all
spacings
tested.
neighbouring
micro-LEDs/electrodes,
relative
influence
on
13-fold
less
compared
(p<0.05).
outcomes
this
show
higher
optogenetic
results
reduced
interaction
which
could
increase
number
independent
channels
implant.
Increased
ability
activate
more
than
one
simultaneously
lead
better
speech
perception
implant
recipients.
Brain stimulation,
Journal Year:
2023,
Volume and Issue:
16(5), P. 1486 - 1500
Published: Sept. 1, 2023
Cochlear
implants
(CIs)
restore
activity
in
the
deafened
auditory
system
via
electrical
stimulation
of
nerve.
As
spread
electric
current
biological
tissues
is
rather
broad,
spectral
information
provided
by
CIs
limited.
Optogenetic
nerve
has
been
suggested
for
artificial
sound
coding
with
improved
selectivity,
as
light
can
be
conveniently
confined
space.
Yet,
foundations
optogenetic
strategies
remain
to
established.
Here,
we
parametrized
stimulus-response-relationships
pathway
gerbils
stimulation.
Upon
activation
waveguide-based
spiral
ganglion,
recorded
neuronal
midbrain,
which
neural
representations
spectral,
temporal,
and
intensity
found.
Screening
a
wide
range
optical
stimuli
taking
properties
CI
emitters
into
account,
aimed
optimize
stimulus
paradigms
potent
energy-efficient
pathway.
We
report
that
efficient
builds
on
integration
millisecond
built
from
microsecond
pulses,
optimally
accommodate
power-efficient
laser
diode
operation.
Moreover,
performed
an
activity-level-dependent
comparison
acoustic
order
estimate
dynamic
maximal
amenable
single
channel
encoding,
indicate
it
complies
well
speech
comprehension
typical
conversation
(65
dB).
Our
results
provide
first
framework
development
future
hearing
restoration.
iScience,
Journal Year:
2023,
Volume and Issue:
26(10), P. 107725 - 107725
Published: Aug. 26, 2023
Hearing
loss
is
the
most
common
human
sensory
deficit.
Severe-to-complete
sensorineural
hearing
often
treated
by
electrical
cochlear
implants
(eCIs)
bypassing
dysfunctional
or
lost
hair
cells
direct
stimulation
of
auditory
nerve.
The
wide
current
spread
from
each
intracochlear
electrode
array
contact
activates
large
sets
tonotopically
organized
neurons
limiting
spectral
selectivity
sound
coding.
Despite
many
efforts,
an
increase
in
number
independent
eCI
channels
seems
impossible
to
achieve.
Light,
which
can
be
better
confined
space
than
electric
may
help
optical
(oCIs)
overcome
shortcomings.
In
this
review,
we
present
state
optogenetic
encoding.
We
highlight
coding
strategy
development
capitalizing
on
that
requires
fine-grained,
fast,
and
power-efficient
real-time
processing
controlling
dozens
microscale
emitters
as
emerging
research
area.
Emerging
applications
of
optical
technologies
are
driving
the
development
miniaturised
light
sources,
which
in
turn
require
fabrication
matching
micro-optical
elements
with
sub-1
mm
cross
sections
and
high
quality.
This
is
particularly
challenging
for
spatially-constrained
biomedical
where
reduced
dimensionality
required,
such
as
endoscopy,
optogenetics,
or
implants.
Planarisation
a
lens
by
Fresnel
approach
was
adapted
conical
(axicon)
made
direct
femtosecond
780
nm/100
fs
laser
writing
SZ2080™polymer
photo-initiator.
Optical
characterisation
positive
negative
fraxicons
presented.
Numerical
modeling
fraxicon
performance
under
illumination
incoherent
spatially
extended
sources
compared
ideal
case
plane
wave
illumination.
Considering
potential
rapid
replication
soft
polymers
resists,
this
holds
great
promise
most
demanding
technological
applications.
